Fiberoptic coupler for coupling an optical fiber to a laser light source

ABSTRACT

A coupler for efficiently coupling a laser light source to a fiberoptic catheter. The coupler contains coding for determining information about the catheter, such as the size of the optical fiber catheter which it is coupling.

This is a division of application No. 07/228,278, filed Aug. 4, 1988U.S. Pat. No. 4,919,508.

BACKGROUND OF THE INVENTION

The invention relates to an apparatus for coupling an optical fiber to alaser light source. More particularly, this invention relates to a quickdisconnect coupler which can mate optical fibers of varying size to alaser light source, the coupler of this invention being able to detectinformation concerning a characteristic such as size, of the opticalfiber being mated to the laser light source.

In the field of medicine, it is desirable to insert optical fibercatheters into the human body to probe and inspect various portions ofthe body. One such technique is to surgically insert a catheter into amain blood vessel and pass the catheter to various organs, such as theheart, for inspection. A technique being used today is to insert anoptical fiber catheter attached to a laser energy source into the bodyand then use laser pulses to destroy materials blocking blood vessels orremove any material towards which the optical fiber catheter directs thelaser energy.

Obviously, each catheter can be employed with only one patient.Accordingly, the catheters are disposable. Since the size of the bloodvessels in human bodies varies according to age and physical attributes,different size fiberoptic catheters are needed. Therefore, a quickconnect/disconnect feature for attaching the fiberoptic catheter to alaser light source is needed.

The optical coupler for attaching an optical fiber catheter to a lasersource must accurately align the optical fiber with the light source topermit near 100% coupling of the laser light into the optical fiber.This requires a particularly accurate coupler.

Various types of quick connect tubing couplers are known in the art. Anexample is U.S. Pat. No. 3,032,359 to Cator, May 1, 1962, whichdiscloses a snap action coupler for tubing having a locking means toprevent leakage at the coupler. A more recent example is shown in U.S.Pat. No. 4,114,853 issued Sep. 19, 1978 to Medvick wherein a closelyfitting male member provides a releasable coupling with a female member.The known tubing couplers are designed to provide a repeatable leak freeseal between two tubes. No use with optical fibers is made or suggested.

Optical fiber couplers such as those disclosed in U.S. Pat. No.4,435,036 to Sasakawa and U.S. Pat. No. 4,607,911 to Rhodes show the useof a two part connector, the two parts being coupled by threadedengagement. Neither coupler is of a quick disconnect design nor does thecoupler provide any information about the optical fibers being coupled.Likewise, the directional coupler disclosed in U.S. Pat. No. 4,423,922to Porter uses a threaded engagement of an optical fiber and does notprovide any information about the fiber being coupled.

When employing fibers of varying size, it is important to know the sizeof the fiber being attached to the laser source. When employing lasersto vaporize or otherwise remove material, the energy density per laserbeam pulse is critical. Too great an energy density may damage humantissue which was not to be removed or cause damage to the optical fiber.As the size of the fiber varies, the energy density per pulse will alsovary. Therefore, in addition to accurately aligning and coupling anoptical fiber catheter to a laser light source, the optical couplershould recognize the size of fiber catheter to which it is coupling sothat the energy emitted by the laser can be controlled.

SUMMARY OF THE INVENTION

The present invention is a quick disconnect coupler for an optical fiberwhich accurately aligns the optical fiber to a laser light source andconveys information concerning a characteristic of the fiber, such asthe size of the fiber which is being coupled. The coupler comprises afirst connector portion having a locking groove which permits accuratealignment of the fiber to a second connector portion mounted on thelaser light source.

A means for providing information indicative of the optical fiber iscontained in the first connector portion. The second connector portionis removably connected to the first connector portion and contains meansfor decoding information about the fiber to which it is being coupled.Information may be coded in the first connector portion by a series ofgrooves whose position and number provide information as to its opticalfiber size. A series of sensors contained in the second connectorportion of the coupler determines the coding of the grooves and providesinformation as to the size, e.g., diameter, of the fiber being coupledto the laser light source.

The coupler may have a male locating pin contained in the firstconnector portion and a cooperating female receptacle in the secondconnector portion. A series of grooves in the male locating pin mayprovide information which can be decoded by a series of microswitches inthe female receptacle.

In an alternative embodiment, information may be coded in the firstconnector portion by a series of relief openings or slots whose presenceand location are related to the optical fiber characteristics. A seriesof sensors contained in the second connector portion determines thecoding of the relief openings and provides information as to the size,diameter, or other characteristics of the fiber catheter being coupledto the laser light source.

The preferred embodiment is described in relation to a fiber deliverysystem adapted to be inserted in a subject through a catheter. Ofcourse, the present invention can be employed with other applications inwhich laser energy is directed along an optical fiber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of the laser fiberoptic catheter system employingthe coupler of the present invention;

FIG. 2a is a drawing of the male portion of the optical fiber catheter;

FIG. 2b is a cross-sectional view of the coupler in a mated position;

FIG. 3 is a detailed view of an electrical microswitch sensing a groove;

FIG. 4 is a schematic drawing of a circuit for determining the presenceand size of a fiberoptic catheter;

FIG. 5 is a cross-sectional view of an alternative embodiment of thecoupler shown in a mated position.

FIG. 6 is a cross-sectional view of the male portion showing the reliefopenings;

FIG. 7 is a schematic drawing of a microprocessor controlled circuit foruse with the invention; and

FIG. 8 is a flow chart of the microprocessor sequencing within thecircuit of FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Shown in FIG. 1 is a layout of the overall system employing thefiberoptic coupler of the present invention. A laser source 10 containsthe power supplies and laser optics to output a laser light beam of adesired energy level. The laser is controlled by a remote isolationcontroller 12 which controls the intensity and duration of the laserpulse via an optically isolated cable 14. Optical coupler 20 of thepresent invention connects a fiberoptical catheter 22 to laser source10. Fiberoptic catheter 22 can be surgically inserted into the groin orother area of a patient 40. Associated within laser source 10 iselectronic circuit 60 used in conjunction with optical coupler 20 todetermine the presence and size of fiberoptic catheter 22 which isconnected to laser source 10.

Fiberoptic coupler 20 as shown in FIG. 2a comprises a male plug portion30 having a locating pin 32 which is clad about or coupled to an end offiberoptic catheter 22. Male plug 30 contains a locking groove 34 andfiber diameter indicating grooves 36. Tip 38 of locating pin 32 istapered to allow easy insertion of the pin within the female receptacleportion of the optical coupler. Enlargement 40 of male plug portion 30can be used as a handle and provides a means for grasping and insertinga disposable catheter into the female portion. Enlarged region 40 may beplastic and have a silicon rubber support 42 extending away from thehandle towards fiberoptic catheter 22 to provide support for and smoothflexing of catheter 22.

A cross-sectional view of fiberoptic coupler 20 in a mated position isshown in FIG. 2b. Female receptacle portion 44 of optical coupler 20 isconnected to receive energy from laser source 10. Locating pin 32 can beseated within metal female housing 44 which contains a spring loadedlocking plunger 46 which presses against locking groove 34 to provide arigid and accurate alignment of tip end 38 of male plug portion 30. Thisaccurately aligns the optical fiber of catheter 22 to laser source 10.Also contained within housing 44 is a series of microswitches 48, 50,52, 54 and 56 which sense the presence or absence of size indicatinggrooves 36 at corresponding locations along locating pin 32.

Microswitch 48 is shown in detail in FIG. 3 wherein an actuating member62 causes contacts of switch 48 to be opened or closed depending uponwhether a groove is located in a position to depress actuating member62. Electrical connections are made to microswitch 48 via leads 64. Theswitch is of standard commercially available design and can beelectrically connected to be either normally opened or normally closed.

The output of the switches is sensed by circuit 60 shown in detail inFIG. 4 wherein switches 48-56 are shown as making contact to ground whenclosed. Connected to each switch is a transistor network containing pullup resistors 70, 72, 74, 76 and 78 connected to transistors 80, 82, 84,86 and 88, respectively, as shown. Transistors 80-88 have load resistors79, 81, 83, 85 and 87, respectively, connecting the transistors to apower supply. The emitter of each transistor is connected to ground.When one of microswitches is closed, the associated transistor has itsbase voltage grounded causing the voltage at the collector to rise toapproximately the power supply voltage. The conduction states oftransistors 80-88 cause currents to flow through resistors 90, 92, 94,96 and 98 which, in turn, cause voltage drops across resistors 100, 102,104, 106 and 108. Thus, a voltage is applied to operational amplifier110. This voltage is uniquely related to which of switches 48-56 isclosed. The voltage applied to amplifier 110 contains informationconcerning which combination of switches is closed. The gain ofoperational amplifier 110 is controlled, in part, by the value ofresistor 112. The output of amplifier 110 is a DC analog voltage whichis related to which of switches 48-56 are opened or closed. The analogoutput is applied through resistor 116 to a voltage controlledoscillator 120. Voltage controlled oscillator 120 can be fine-tuned byresistors 122, 124, 126, 132 and 134 and capacitors 128 and 130 toproduce an AC output whose frequency is directly related to DC voltageinput, and therefore, to which of switches 48-56 are closed. This ACoutput of voltage controlled oscillator 120 is through buffer transistor146 with optical coupling provided by photodiode 140 and phototransistor 150 to remote controller 12 which uses the frequency of thesignal to control the energy emitted per pulse by laser source 10.

Additionally, the output across the resistor network 100-108 is providedto one input of operational amplifier 160. Resistors 162 and 164 set areference voltage at the other input of amplifier 160. With thisarrangement, amplifier 110 acts as a comparator to provide an outputwhich is indicative of the presence of any optical fiber and can be usedto control the opening and closing of a shutter of laser source 10.

Any number of different circuit schemes can be devised to handle theoutput of the microswitches used in the electrical sensing of theoptical fiber. The optical fiber coding of the male plug portion shownin FIG. 2b could be coded as 01000 and correspond to a logic staterepresented by a binary 8.

An alternate embodiment for encoding information about the optical fiberis shown in FIG. 5. The male plug portion 30 is shown with fiberopticcatheter 22 connected to enlarged handle region 40 and having a support42 of silicon rubber or other material. Enlarged handle region 40contains a number of relief slots 180 whose presence or absence isindicative of the characteristics of the fiberoptic catheter 22.

Female housing 44 contains a series of plungers 184 in longitudinalbores of the female housing 44. Plungers 184 are urged upward by springs186 which push against the plunger 184 and spring keeper cover 188.Plungers 184 are narrowed at its one end to fit into relief slot 180, ifpresent. At the end of plunger 184, away from male portion 30, theplunger activates a microswitch 248 having an actuating member 62 whichis triggered through a lever arm 66.

To ensure proper angular orientation between female housing 44 and maleplug portion 30, a pin 100 is placed in housing 44 to rotationally alignand hold housing 44 and plug 30 in a fixed position.

As can be seen in FIG. 5, one plunger 184 is seated in relief slot 180causing microswitch 250 to close while another plunger has failed tofind a relief slot 180 and causes the microswitch 248 to remain open.

A cross-sectional view of FIG. 5 taken through the enlarged handleregion 40 showing the junction of the female housing 44 and male plug 30is shown in FIG. 6. Relief slot regions 180, whose presence or absenceare indicative of the characteristics of the fiberoptic catheter, areplaced radially about the handle region. Rotational alignment pin 190 isshown in a bore of handle 40.

A circuit for decoding information about the fiberoptic catheter whichemploys a microprocessor is shown in FIG. 7. Switches 248, 250, 252 and254, corresponding to the microswitches shown in FIG. 5, are activatedby plungers 184. The switches are of a single pole double throw type andconnect to a switch debouncer 270. Capacitors 260 and diodes 262 connectthe switching lines to ground or the supply voltage as shown in FIG. 7.The capacitors and diodes filter high frequency signals and high voltagespikes that might be picked up by the switch lead wires.

When none of the switches 248-254 are activated, the outputs of theswitch debouncer 270 will be high. All high signals to the input ofmicroprocessor controller 280 indicates that there is no fiberopticcatheter in the fiberoptic coupler. When a fiberoptic catheter ispresent, a combination of high and low signals will indicate thediameter or other characteristic of the catheter. A total of fifteendifferent combinations can be decoded from a four switch input circuit.

A synchronizer clock signal 272 can be used as a strobe for the switcherdebouncer 270. This will ensure that all inputs from switches 248-254are stable when the microcontroller 280 reads its inputs.

NAND gates 290 and 291 and NOR gate 293 are used to generate viahardware a signal indicating that a catheter is not in place. Thissignal is used as an input signal to an EPROM which performs ahardware-software error check. A low voltage signal indicates a catheteris not in place and a high signal indicates that a fiber is in place.

Microprocessor 280 controls the laser power output to the fiberopticcatheter based on the information decoded from the fiberoptic couplerand selected energy density. Microprocessor 280 receives inputs from thefiberoptic coupler through the switch debouncer circuit 270, thedoctor's desired energy density through input 290, and a total laserenergy output from detector 292. A beam splitter 296 can be used todivert a portion of the laser beam to the detector 292. Themicroprocessor enables the pulsing of the laser 10 and adjusts avariable iris 294 to control the laser energy delivered to optical fibercatheter 22.

A flow chart for the microprocessor 280 is shown in FIG. 8. Uponinitialization, the microprocessor reads the desired energy density step300 which is selected by a doctor to achieve the desired ablationconditions for the fiberoptic catheter. Next, in step 310, themicroprocessor reads the fiber characteristics presented to it from theoptical coupler 20 through switch debounce 270. A calculation is made bythe microprocessor in step 320 to determine the desired laser powersettings to achieve the selected energy density in the specific opticalfiber being used. A reading is made of the actual laser power in step330. A comparation of the actual laser output power to the desired powerlevel is made to produce an error signal in step 340. The error signalis used to adjust a variable iris 294 in step 350 so that the desiredenergy density is sent through optical fiber catheter 22.

Other encoding means such as magnetic or optical sensing schemes couldbe developed to work in conjunction with the design of the opticalcoupler of the present invention.

The present invention provides a fiberoptic coupler which accuratelyaligns an optical fiber to a laser light source and is able to detectthe presence or absence of a fiber as well as to determine sufficientinformation as to fiber size to identify the diameter of the fiber beingused.

While the invention has been described in connection with what ispresently considered to be the preferred embodiment, it is to beunderstood that the invention is not limited to the disclosed embodimentbut can be intended to cover its modifications and equivalentarrangements within the spirit and scope of the appended claims.

What is claimed is:
 1. A plug portion of a fiberoptic coupler,comprising:a body including a handle and an extension protruding fromsaid handle; means for attaching said body to a fiberoptic; and means,disposed on said body, for physically indicating a size of thefiberoptic.
 2. A plug portion as claimed in claim 1, wherein:said bodyincludes a locating pin having a central axial bore and an enlargedhandle having a diameter greater than a diameter of said locating pin,said handle attached at a longitudinal end of said locating pin, saidlocating pin being attached to a first side of said handle, said handlesupporting said fiberoptic; and said means for attaching said plugportion to a fiberoptic includes means for attaching said fiberoptic insaid bore of said locating pin and a support for said fiberopticattached to a second side of said handle.
 3. A plug portion as claimedin claim 2, further comprising means for attaching said plug portion toa light emitting member including:a tapered tip of said locating pinproviding for accurate and easy attachment of said pin and the lightemitting member; and a locking groove provided on said locating pin atthe longitudinal end that accepts a locking mechanism of the lightemitting member.
 4. A plug portion as claimed in claim 2, wherein saidmeans for indicating a size of the fiberoptic includes at least onefiber diameter indicating groove.
 5. A plug portion as claimed in claim2, wherein said means for indicating a size of the fiberoptic includes aplurality of relief slots provided on the enlarged handle, with apresence or absence of said slots providing information indicative ofcharacteristics of the fiberoptic.
 6. A male plug portion as claimed inclaim 5, wherein said slots are located radially about said enlargedhandle.
 7. A plug portion as claimed in claim 1, wherein said means forindicating a size of the fiberoptic includes means to indicate thediameter of the fiberoptic.
 8. A plug portion as claimed in claim 1,wherein said fiberoptic to which said body is attached via said meansfor attaching includes a single optical fiber.
 9. A plug portion of afiberoptic coupler according to claim 1, wherein said handle is adifferent size than said extension.
 10. A plug portion of a fiberopticcoupler according to claim 9, wherein said handle is larger than saidextension.
 11. A plug portion of a coupler for a fiberoptic catheter,comprising:a catheter having a fiberoptic therein; a body; means forattaching said body to the catheter; and means, disposed on said body,for physically providing information indicative of the catheter.
 12. Aplug portion as claimed in claim 11, wherein said fiberoptic includes asingle optical fiber.
 13. A plug portion as claimed in claim 11, whereinsaid information is representative of the size of the catheter.
 14. Aplug portion as claimed in claim 12, wherein said information isrepresentative of a diameter of the optical fiber.
 15. A plug portion asclaimed in claim 11, wherein:said body includes a locating pin having acentral axial bore and an enlarged handle having a diameter greater thana diameter of said locating pin, said handle attached at a longitudinalend of said locating pin, said locating pin being attached to a firstside of said handle, said handle supporting said catheter; and saidmeans for attaching said plug portion to a catheter includes means forattaching said catheter in said bore of said locating pin and a supportfor said catheter attached to a second side of said handle.
 16. A plugportion as claimed in claim 15, wherein said means for attaching saidplug portion to a light emitting member includes:a tapered tip of saidlocating pin providing for accurate and easy attachment of said pin andsaid light emitting member; and a locking groove provided on saidlocating pin at the longitudinal end that accepts a locking mechanism ofthe light emitting member.
 17. A plug portion as claimed in claim 15,wherein said means for providing information includes at least one fibersize indicating groove that informs the light emitting member of thesize of the catheter.
 18. A plug portion as claimed in claim 15, whereinsaid means for providing information includes a plurality of reliefslots located radially about said enlarged handle.
 19. A plug portion ofa fiberoptic coupler, comprising:a body including a handle and anextension protruding from said handle; means for attaching said body toa fiberoptic; and means, disposed on said body, for physically providinginformation indicative of the fiberoptic.
 20. A plug portion as claimedin claim 19, wherein said fiberoptic includes a single optical fiber.21. A plug portion of a fiberoptic coupler according to claim 19,wherein said handle is a different size than said extension.
 22. A plugportion of a fiberoptic coupler according to claim 21, wherein saidhandle is larger than said extension.